1. Field of the Invention
The present invention is directed to a grinding apparatus and method, and in particular to a pavement grinding apparatus and method for grinding close to curbs and other raised structures.
2. Description of the Prior Art
Pavement grinders are used for grinding concrete and asphalt surfaces to remove irregularities in the road surface, to provide texture to the surface to prevent skidding and to groove the surface to facilitate water drainage. Grinding, texturing and grooving are used on pavement surfaces including roads and streets, airport runways and bridge decks, industrial plants, stock pens and barns. The diamond tip blades that are used to grind the concrete or asphalt surfaces are mounted on a rotating arbor. Typical grinding machines have the arbor mounted on an under carriage so that both ends of the arbor are supported by bearing assemblies capable of sufficiently supporting the arbor while enduring the high stresses associated with pavement grinding. Both end portions of the arbor are typically mechanically driven by a system of belts and pulleys. Such grinders are large, heavy machines with sufficient mass to impart the high forces necessary for effective pavement grinding.
Smaller pavement saws are utilized to maintain expansion joints in the roadway and to separate damaged sections of pavement for easy removal. Such saws typically have a narrow cut and do not have sufficient power or mass for pavement grinding. Other specialized grinders are used to create slots for reflectors or to create rumble strips. Examples of grinders are shown in U.S. Pat. No. 5,354,146 assigned to Diamond Surface, Inc., and U.S. Pat. No. 5,161,910, also assigned to Diamond Surface, Inc. An example of a grinder for slot cutting is shown in U.S. Published Application 2005 0196240. Although these grinding and cutting devices have proven to be useful and efficient for their intended purposes, they are not suited for performing certain grinding functions.
Challenges exist for close proximity grinding by curbs and drains as most large grinders cannot get sufficiently close to the curb. A further problem compounding the difficulty in grinding close to curbs and drains is the angle between the lower apron or drainage portion to be ground next to the curb wall and the surface of the road or street. Often the road or street has a central crown and slopes slightly to the edges. The lower drainage apron portion of the curb also extends substantially horizontally, but typically the crown does not continue on to the apron portion of the curb. Therefore, the lower portion of a curb is tilted slightly relative to the adjacent road surface. This causes problems for grinding the lower apron portion of the curb as the grinder has an arbor extending at an angle to this lower surface rather than being parallel with the surface of the lower drainage portion of the curb, as is required for satisfactory grinding.
In addition, grinding such curbs presents problems with regard to grinder access. A common problem with such curbs is that a section of the drainage curb portion is slightly raised and/or offset, often leading to pooling and interrupting proper drainage. Transportation departments often require grinding to within a specified distance from the curb wall, typically 14-18 inches. Smaller prior art devices have not had the power and width to grind the surface of such portions in a satisfactory manner. The options have typically been to remove the section or to attempt to grind with smaller, hand maneuvered devices. Such manual devices have not been satisfactory, as the grinding is uneven and the process is too time-consuming and inefficient due to the grinding head being too narrow with insufficient power. The larger pavement grinding devices have arbors that do not get sufficiently close to the vertical portion of the curb to perform the grinding operation correctly. Such grinders typically have the arbor positioned on an under carriage and centered on the grinding device. Such an arrangement does not allow access to the curb to grind even a portion of the curb.
It can be seen then that a new and improved grinding apparatus is needed. Such a grinding apparatus should provide for a head having sufficient width and power to grind a curb. In addition, the head should be configured so that it can grind close enough to the raised curb portion to allow proper drainage. Such a device should also provide for changing the angle of the grinding head so that the grinder may be on a surface not aligned with the lower portion of the curb while grinding close to a raised structure. The present invention addresses these as well as other problems associated with close proximity grinding.